U.S. patent application number 13/941242 was filed with the patent office on 2014-01-16 for off-wall electrode devices and methods for nerve modulation.
The applicant listed for this patent is BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to JAMES M. ANDERSON, DEREK C. SUTERMEISTER, HUISUN WANG.
Application Number | 20140018794 13/941242 |
Document ID | / |
Family ID | 48914429 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140018794 |
Kind Code |
A1 |
ANDERSON; JAMES M. ; et
al. |
January 16, 2014 |
OFF-WALL ELECTRODE DEVICES AND METHODS FOR NERVE MODULATION
Abstract
Systems for nerve modulation are disclosed. An example system
for nerve modulation may include a catheter shaft having a proximal
end, a distal end and lumen extending therebetween. An inflatable
member may be fluidly connected to the lumen of the catheter shaft
proximate the distal end of the catheter shaft. The inflatable
member may have an outer wall defining a groove in an outer surface
of the inflatable member. An electrode may be disposed in or under
the groove.
Inventors: |
ANDERSON; JAMES M.;
(FRIDLEY, MN) ; SUTERMEISTER; DEREK C.; (HAM LAKE,
MN) ; WANG; HUISUN; (MAPLE GROVE, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOSTON SCIENTIFIC SCIMED, INC. |
MAPLE GROVE |
MN |
US |
|
|
Family ID: |
48914429 |
Appl. No.: |
13/941242 |
Filed: |
July 12, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61671536 |
Jul 13, 2012 |
|
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|
Current U.S.
Class: |
606/41 |
Current CPC
Class: |
A61B 2018/00255
20130101; A61B 2018/00232 20130101; A61B 18/1492 20130101; A61B
2218/002 20130101 |
Class at
Publication: |
606/41 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Claims
1. A system for nerve modulation, comprising: a catheter shaft
having a proximal end, a distal end and lumen extending
therebetween; an inflatable member fluidly connected to the lumen
of the catheter shaft proximate the distal end of the catheter
shaft, the inflatable member having an outer wall defining a groove
in an outer surface of the inflatable member; and an electrode
disposed in or under the groove.
2. The system of claim 1 wherein the groove extends longitudinally
along at least a portion of the outer wall of the inflatable
member.
3. The system of claim 1 wherein the groove extends in a helical
manner along at least a portion of the outer wall of the inflatable
member.
4. The system of claim 1 wherein the groove is a circumferential
groove.
5. The system of claim 1 wherein the groove is one of a plurality
of grooves.
6. The system of claim 5 wherein the plurality of grooves are
regularly spaced on the inflatable member.
7. The system of claim 5 wherein the electrode is one of a
plurality of electrodes and wherein each of the plurality of
electrodes is disposed in or under one of the plurality of
grooves.
8. The system of claim 7 wherein at least one electrode is disposed
in or under each of the plurality of grooves.
9. The system of claim 1 further comprising a plurality of small
holes in the outer wall of the inflatable member proximate each
electrode.
10. The system of claim 9 wherein the plurality of small holes are
in the groove.
11. The system of claim 9 wherein each of the plurality of small
holes has a maximum width of between 10 and 20 microns.
12. The system of claim 1 wherein the electrode is in the
groove.
13. The system of claim 1 wherein the inflatable member further
comprises an inner balloon disposed within the inflatable
member.
14. The system of claim 13 wherein the outer wall of the inflatable
member comprises a compliant material and the inner balloon
comprises a non-compliant material.
15. The system of claim 13 wherein the electrode is disposed
between the outer wall of the inflatable member and the inner
balloon.
16. A system for nerve modulation, comprising: a catheter shaft
having a proximal end, a distal end and lumen extending
therebetween; an inflatable member fluidly connected to the lumen
of the catheter shaft proximate the distal end of the catheter
shaft, the inflatable member having an outer wall defining a
plurality of grooves in an outer surface of the inflatable member;
a plurality of electrodes disposed within the plurality of grooves;
and a plurality of holes in the outer wall of the inflatable member
proximate each electrode.
17. A system for nerve modulation, comprising: a catheter shaft
having a proximal end, a distal end and at least one lumen
extending therebetween; an outer balloon fluidly connected to the
catheter shaft proximate the distal end of the catheter shaft, the
outer balloon having an outer wall defining a groove in an outer
surface of the outer balloon; an inner balloon fluidly connected to
the catheter shaft proximate the distal end of the catheter haft
and disposed within the outer balloon; and at least one electrode
disposed in or under the groove.
18. The system of claim 17 wherein the at least one electrode is
disposed on an outer surface of the inner balloon and disposed
under the groove.
19. The system of claim 17 further comprising a plurality of holes
in the outer wall of the outer balloon proximate the at least one
electrode.
20. The system of claim 17 wherein the groove is one of a plurality
of grooves.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to U.S. Provisional Application Ser. No. 61/671,536, filed Jul. 13,
2012, the entirety of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates to methods and apparatuses
for modulating nerves through the walls of blood vessels. Such
modulation may include ablation of nerve tissue or other modulation
technique.
BACKGROUND
[0003] Certain treatments require temporary or permanent
interruption or modification of select nerve functions. One example
treatment is renal nerve ablation, which is sometimes used to treat
conditions related to congestive heart failure. The kidneys produce
a sympathetic response to congestive heart failure, which among
other effects, increases the undesired retention of water and/or
sodium. Ablating some nerves running to the kidneys may reduce or
eliminate this sympathetic function, providing a corresponding
reduction in the associated undesired symptoms. For example, a
renal nerve ablation procedure is often used to lower the blood
pressure of hypertensive patients.
[0004] Many nerves (and nervous tissue such as brain tissue),
including renal nerves, run along the walls of or in close
proximity to blood vessels and these nerves can be accessed
intravascularly through the blood vessel walls. In some instances,
it may be desirable to ablate or otherwise modulate perivascular
renal nerves using a radio frequency (RF) electrode. Such
treatment, however, may result in thermal injury to the vessel at
the electrode and other undesirable side effects such as, but not
limited to, blood damage, clotting, and/or protein fouling of the
electrode. To prevent such undesirable side effects, some
techniques attempt to increase the distance between the vessel
walls and the electrode. In these systems, however, the electrode
may inadvertently contact the vessel walls.
[0005] Therefore, there remains room for improvement and/or
alternatives in providing systems and methods for intravascular
nerve modulation.
SUMMARY
[0006] The disclosure is directed to several alternative designs
and methods of using medical device structures and assemblies.
[0007] Accordingly, some embodiments pertain to a system for nerve
modulation including a device having an inflatable member at the
distal end. The inflatable member includes one or more grooves
formed on its surface and one or more electrodes disposed in the
grooves. Small holes in the grooves proximate each the one or more
electrodes allow for the seepage of inflation fluid from the
interior of the inflatable member. The one or more grooves may be
longitudinal, circumferential, or helical. There may be one, two,
or more electrodes in each of the one or more grooves. The grooves
and the electrodes may be arranged to provide circumferential
coverage. The grooves and the electrodes are arranged such that
when the inflation member is inflated in a blood vessel, the
electrodes are spaced from the wall of the blood vessel.
[0008] Some embodiments pertain to a system for nerve modulation
including a device having a double-walled balloon on the distal
end. The outer balloon may include one or more grooves as described
above. One or more electrodes may be placed in the one or more
grooves or under the one or more grooves between the outer balloon
and the inner balloon. Small holes in the grooves proximate each
the one or more electrodes allow for the seepage of inflation fluid
from the interior of the outer balloon. The grooves and the
electrodes are arranged such that when the inflation member is
inflated in a blood vessel, the electrodes are spaced from the wall
of the blood vessel. The outer balloon may be made from a more
compliant material and the inner balloon may be made from a less
compliant material.
[0009] The summary of some example embodiments is not intended to
describe each disclosed embodiment or every implementation of the
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present disclosure may be more completely understood in
consideration of the following detailed description of various
embodiments in connection with the accompanying drawings, in
which:
[0011] FIG. 1 is a schematic view illustrating a renal nerve
modulation system in situ.
[0012] FIG. 2 is an isometric view of the distal end portion of an
exemplary renal nerve system.
[0013] FIG. 3 is a cross-sectional view illustrating the
illustrating the distal end portion of an exemplary system in
situ.
[0014] FIG. 4 is a detail cross-sectional view illustrating a
portion of an exemplary renal nerve modulation system.
[0015] FIG. 5 is an isometric view of the distal end portion of an
exemplary renal nerve modulation system.
[0016] FIG. 6 is an isometric view of the distal end portion of an
exemplary renal nerve modulation system.
[0017] FIG. 7A is a schematic view illustrating the distal end
portion of an exemplary renal nerve modulation system in situ.
[0018] FIG. 7b is a cross-sectional view of the system of FIG. 7A
along the section indicated in FIG. 7A.
[0019] FIG. 7C is a schematic cross-sectional view of an exemplary
renal nerve modulation system.
[0020] FIG. 8 is a schematic side view of an exemplary renal nerve
modulation system.
[0021] FIG. 9 is a detail view of an exemplary renal nerve
modulation system.
[0022] FIG. 10 is a schematic side view of an exemplary renal nerve
modulation system.
[0023] FIG. 11 is a schematic cross-sectional view of an exemplary
renal nerve modulation system.
[0024] FIG. 12 is a schematic side view of an exemplary renal nerve
modulation system.
[0025] While embodiments of the present disclosure are amenable to
various modifications and alternative forms, specifics thereof have
been shown by way of example in the drawings and will be described
in detail. It should be understood, however, that the intention is
not to limit aspects of the disclosure to the particular
embodiments described. One the contrary, the intention is to cover
all modifications, equivalents, and alternatives falling within the
spirit and scope of the present disclosure.
DETAILED DESCRIPTION
[0026] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in the specification.
[0027] All numeric values are herein assumed to be modified by the
term "about," whether or not explicitly indicated. The term "about"
generally refers to a range of numbers that one of skill in the art
would consider equivalent to the recited value (i.e., having the
same function or result). In many instances, the term "about" may
be indicative as including numbers that are rounded to the nearest
significant figure.
[0028] The recitation of numerical ranges by endpoints includes all
numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75,
3, 3.80, 4, and 5).
[0029] Although some suitable dimension ranges and/or values
pertaining to various components, features, and/or specifications
are disclosed, one of skill in the art, incited by the present
disclosure, would understand desired dimensions, ranges and/or
values many deviate from those expressly disclosed.
[0030] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the content clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the content clearly
dictates otherwise.
[0031] The following detailed description should be read with
reference to the drawings in which similar elements in different
drawings are numbered the same. The detailed description and the
drawings, which are not necessarily to scale, depict illustrative
embodiments and are not intended to limit the scope of the
disclosure. The illustrative embodiments depicted are intended only
as exemplary. Selected features of any illustrative embodiment may
be incorporated into an additional embodiment unless clearly stated
to the contrary.
[0032] While the devices and methods described herein are discussed
relative to renal nerve modulation, it is contemplated that the
devices and methods may be used in other applications where
ablation or modulation is desired such as nerve modulation and/or
ablation near other vessel lumens. It is contemplated that the
devices and methods may be used in other treatment locations and/or
applications where nerve modulation and/or other tissue modulation
including heating, activation, blocking, disrupting, or ablation
are desired, such as, but not limited to: blood vessels, urinary
vessels, or in other tissues via trocar and cannula access. For
example, the devices and methods described herein can be applied to
hyperplastic tissue ablation, cardiac ablation, pulmonary vein
isolation, tumor ablation, benign prostatic hyperplasia therapy,
nerve excitation or blocking or ablation, modulation of muscle
activity, hyperthermia or other warming of tissues, etc. The
disclosed methods and apparatus can be applied to any relevant
medical procedure, involving both human and non-human subjects. The
term modulation refers to ablation and other techniques that may
alter the function of affected nerves and other tissue.
[0033] In some instances, it may be desirable to ablate
perivascular renal nerves with targeted tissue heating. However, as
energy passes from an electrode to the desired treatment region the
energy may heat the fluid (e.g. blood) and tissue as it passes. As
more energy is used, higher temperatures in the desired treatment
region may be achieved, but may result in some negative side
effects, such as, but not limited to, thermal injury to the vessel
wall, blood damage, clotting, and/or electrode fouling. Positioning
the electrode away from the vessel wall may provide some degree of
passive cooling by allowing blood to flow past the electrode while
still allowing the electrode elements to target nerves within about
2.5 mm of the luminal surface, where the perivascular renal nerves
are located. An appropriate amount of energy may properly ablate
the nerve tissue while causing little or no damage to the vessel
wall or to deep tissue such as muscle tissue or the intestinal
walls.
[0034] FIG. 1 illustrates a general overview of a renal nerve
modulation system 10 as it may look during an operation. System 10
includes a renal nerve modulation device 12, which may be inserted
percutaneously into a blood vessel through a guide catheter 14. A
femoral approach is illustrated, though it will be readily
appreciated that the devices and methods described herein may
readily be used with other approaches such as a radial approach.
The scope of the disclosure with regard to the distal end of device
12 will be better understood when the subsequent figures are
discussed, below.
[0035] The proximal end of the device 12 is generally operatively
connected via a control and power wire 16 to a control and power
unit 18. The control and power wire 16 may include an appropriate
number of separate conductors. For example, in some embodiments,
each electrode or set of electrodes is operatively connected to the
control and power unit 18 by separate conductors. Further, some
embodiments may include one or more sensors, such as a thermocouple
or pressure sensor, at the distal end region of the device 12. Each
such sensor may be operatively connected to the control and power
unit 18 by a separate conductor. All these conductors may be part
of control and power wire 16.
[0036] The control and power unit 18 includes appropriate elements
to control the device 12 and provide appropriate feedback. Such
elements may include any standard electric and/or electronic system
control elements. Examples of such elements include power supplies,
switches, displays, programmable interfaces and the like. The
control and power unit 18 may include monitoring elements to
monitor parameters such as power, temperature, voltage, amperage,
impedance, pulse size and/or shape and other suitable parameters as
well as suitable controls for performing the desired procedure. In
some instances, the power element 18 may control a radio frequency
(RF) electrode. The electrode may be configured to operate at a
frequency of approximately 460 kHz. It is contemplated that any
desired frequency in the RF range may be used, such as, for
example, from 400-900 kHz. However, it is contemplated that
different types of energy outside the RF spectrum may be used as
desired.
[0037] Device 12 may also be operatively attached by a fluid inlet
lumen 22 to a fluid source 24 such as a syringe or a pump. The
fluid from the fluid source is preferably a bio-compatible
electrically conductive fluid such as an isotonic saline or the
like. The fluid may also include a radiopaque agent. Some
embodiments of the device may circulate the fluid through the
distal end region of the device and thus may also include a fluid
drainage lumen 26, which may, in turn, be attached to a fluid
collection bag 28 or the like. Some embodiments, as discussed
below, include more than one balloon in the distal end region, and
thus the device may be operatively connected to more than one fluid
source at the proximal end.
[0038] In some embodiments, the control and power unit 18 may
further be connected to one or more return electrode patches 20,
which, during operation, may be located on the abdomen or at
another conventional location on the body. The proximal end of the
system may also include other standard elements (not explicitly
shown), such as a hub, a handle, a guide wire lumen, and the like.
The system 10 may include other elements, not illustrated, such as
guide wires, introducer sheaths and the like. The device 12 may be
removably connected to any or all exterior elements.
[0039] Turning now to FIG. 2, which illustrates the distal end
region of an example device 12, according to a particular
embodiment. The distal end region generally includes a balloon 32,
which is at or near the distal end of a catheter 30 and connected
thereto. The interior of the balloon 32 is fluidly connected to a
fluid inlet lumen in the catheter 30. The catheter 30 may also
include other lumens such as a guidewire lumen 40 and, if desired,
a separate fluid egress lumen. The balloon 32 is movable, through
the introduction and removal of an inflation fluid, between an
inflated state (illustrated) and a collapsed state. When inflated,
the balloon 32 may have a generally circular cross-sectional
profile, interrupted by shallow longitudinal grooves 34. The
particular embodiment illustrated includes three grooves 34, but
may include fewer or more grooves 34 as desired. One or more
electrodes 36 may be at the bottom of each groove. Each electrode
36 may be connected to the control and power unit by a separate
conductor 38. Alternatively, sets of electrodes such as the sets
formed by the electrodes in each groove may share a conductor 38.
It can be appreciated that any combination of electrodes may share
a power connection. For example, each of the two circumferential
sets formed by the three distal electrodes and the three proximal
electrodes may be powered as a unit such that one conductor 38
powers the proximal set and one conductor 38 powers the distal set.
Alternatively, all electrodes may share the same power
connection.
[0040] Variations on the size, shape, number and arrangement of the
electrodes 36 are contemplated. For example, the embodiment
illustrated shows the three proximal electrodes at the same
longitudinal location and the three distal electrodes as the same
longitudinal position. In other embodiments, the longitudinal
position of the electrodes 36 may be staggered such that each
electrode, or no more than two electrodes share the same
longitudinal position. The shape of the electrode is illustrated as
generally oblong, although any convenient shape may be used such as
circular, oval, polygonal and the like. In some embodiments, it is
preferable to avoid electrodes that have exposed sharp edges. The
length (i.e. the dimension of the electrode along the longitudinal
dimension of the device) to width ratio may vary as desired. For
example, the ratio may be 1:1, 1.5:1, 2:1, 3:1, 5:1, 10:1 or other
desired ratio. There may be more or fewer electrodes 36 per groove
34. For example, there may be one, two, three, four other desired
number of electrodes 36 per groove 34. In some embodiments, one or
more of the grooves 34 may be used solely for the purpose of
maintaining blood flow and so there may be no electrodes in one or
more grooves. The relationship between the electrode 36, the
balloon 32 and the grooves 34 will be discussed with respect to
subsequent figures such as FIG. 3, which is a distal end view of
the device 12 of FIG. 2 in situ.
[0041] FIG. 3 illustrates device 12 as it might appear when
inflated and ready to use for a therapeutic procedure. The device
12, when inflated, is preferably sized to center the device 12
within a blood vessel. The balloon 32 may be made from a compliant
or semi-compliant material that may allow the balloon 32 to be used
within blood vessels having a range of diameters. For example, a
balloon having a nominal diameter of 6 mm may, through varying the
inflation pressure, accommodate blood vessels having diameters of
between 5 mm and 7 mm. Of course, devices of varying sizes to
accommodate a range of blood vessels may be manufactured for use.
In some embodiments, the device 12 may include a guidewire lumen 40
defined by a catheter wall 66.
[0042] When inflated for a procedure, the grooves 34 should provide
a gap 42 between the electrodes 36 and the wall of the blood
vessel. The gap may be any appropriate dimension. A gap of over
0.0010'' may be appropriate for some embodiments. In preferred
embodiments, a minimum non-zero gap between the electrodes and the
vessel wall is maintained. The broken lines in FIG. 3 generally
indicate the transmission of RF energy from the electrodes through
the wall of the blood vessel and into the nerve tissue.
[0043] FIG. 4 is a detail view illustrating an electrode 36 and an
associated portion of the wall 44 of the balloon 32 for a device 12
as illustrated in FIG. 2. The balloon wall 44 of a device 12 may
include small holes 48, 50 proximate each operative electrode 36 of
the device 12. Such holes may be in one or more of the side walls
of a groove 34 as indicated at 48 or may be beneath an electrode 36
as indicated at 50, or both. The electrode 36 may also include
holes 46 to permit egress of the fluid flow through holes 50. The
size and quantity of such holes 46, 48, 50 should be such as to
keep the total flow of fluid from the balloon cavity to a low
figure. For example, holes sizes in the range of 10-20, 10-30,
20-30, or 20-40 microns may be appropriate. A total fluid flow of
between 10-20 cubic centimeters (cc)/minute (min) or between 10-30
cc/min or under 50 cc/min may be appropriate in certain
applications.
[0044] An example therapeutic procedure using the embodiment of
FIG. 2 will now be described. A device 12 is inserted
percutaneously into a renal artery using a femoral approach. The
device 12 may be inserted using a guide catheter 14 and/or other
standard devices and procedures such as a guide wire. The device 12
is inserted in its collapsed configuration through, for example,
the guide catheter 14. The guide catheter 14 distal end may be
positioned just proximal the desired location of the therapeutic
procedure and the distal end region of the device may be advanced
out of the guide catheter 14 and into position. Alternatively, the
guide catheter distal end can be positioned at the desired location
with the distal end region of the device 12 inside. The guide
catheter 14 may then be withdrawn proximally, leaving the device 12
in place. Other standard delivery techniques may be employed as
well. Once the distal end region of the device is in place, an
inflation fluid, such as the saline discussed above, is introduced
to inflate the balloon. In this embodiment, a high inflation
pressure is not necessarily needed or desired. Accordingly, the
balloon 32 may be inflated to a pressure of between 0-3 atmosphere
(atm). When the balloon is inflated, the electrodes 36 are held by
the shape of the grooves 34 away from the vessel wall, defining the
gap 42 spacing the electrode 36 from the vessel wall. The inflation
fluid will also begin to seep from holes 46, 48, 50 which may be
present in the particular embodiment. At this point, the electrodes
36 may be activated to generate an RF current. The inflation fluid,
vessel wall, and body tissue complete the circuit between the
electrodes and any return electrodes. The RF current generates heat
in the tissue to denervate the nerve tissue. At the same time, the
inflation fluid seeping out from the balloon and the blood in the
blood vessel flow past the vessel wall and transfer heat from the
portion of the vessel wall nearest the lumen (i.e. the intima and
proximate portions of the media) to prevent damage to the blood
vessel wall. The RF energy may be provided at any effective level.
For example, in some procedures, 1-15 watts for 1-2 minutes is
effective. In some procedures, the device 12 is then withdrawn
using conventional methods. In other procedures, the device 12 may
be repositioned and the denervation procedure using the RF energy
repeated. The reposition may aided by partially or completely
evacuating the inflation fluid from the balloon cavity, to
partially or completely collapse the balloon. The balloon may then
be reinflated at the new location. In some renal nerve denervation
procedures, it may be desirable to denervate a circumferential
section of nervous tissue to interrupt the function of nerves
running along the renal arteries. This may be a contiguous
circumferential section or may include non-contiguous sections that
are at different circumferential and longitudinal locations and are
arranged such that any longitudinally extending nerve is
interrupted by at least one denervated section. In some procedures,
80%, 90% or 95% coverage may be effective. In other words, in some
procedures, denervating 80%, 90% or 95% of a contiguous or
non-contiguous circumferential section may be adequate.
[0045] The above procedure was described as a unipolar procedure,
where the electrodes 36 are used to radiate RF energy to one or
more return electrodes 20 on the body of the patient. However, a
device 12 is also suitable for use with bipolar procedures. In
bipolar procedures, some of the electrodes 36 act as the return
electrode(s), and in some bipolar procedures, the electrodes 36
that act as return electrodes alternate with the alternative
current. Any device 12 where electrodes or sets of electrodes 36
are controlled and powered separately may be suitable for use in a
bipolar procedure. In a bipolar procedure, the RF current passes
from an electrode 36, through the fluid in the blood vessel, the
wall of the blood vessel and the body tissue and then back to the
control and power unit 18 through another electrode 36. Because
unipolar and bipolar operation create different denervation
patterns, it may be desirable to perform unipolar and bipolar
operations during the same procedure.
[0046] Performance may be monitored during the procedure through
the use of sensors in the distal end region and by monitoring the
change in impedance of the current through the body. Appropriate
sensors include temperature sensors such as thermocouples and
pressure sensors. The control and power unit 18 may be programmed
to dynamically respond to changes in the sensor measurements.
[0047] Further, while these example procedures have been described
with respect to the embodiment of FIG. 2 described above, it can be
readily appreciated that the procedure may be used with the other
embodiments described in this specification.
[0048] For example, FIGS. 5 and 6 are isometric views of distal end
regions of devices 12 that are similar to that of FIG. 2, except as
illustrated and described herein. The embodiment of FIG. 5 has
three grooves 34 that extend along the surface of balloon 32 in a
generally helical or spiral fashion. Electrodes 36 are disposed at
the bottom of grooves 34. The helical arrange of the grooves allows
for a wider circumferential distribution of the electrodes. For
example, the six electrodes 36 illustrated in FIG. 5 may be
arranged such that each is approximately 60.degree. from its
nearest two neighboring electrodes 36. In this fashion, the six
electrodes 36 are equally distributed circumferentially around the
body of the balloon 32.
[0049] FIG. 6 illustrates an embodiment having a single groove 34
that extends helically around the body of the balloon. In the
particular embodiment illustrated, the groove 34 extends for a
complete 360.degree. loop. Of course, depending on the desired
arrangement of the electrodes, the groove 34 may extend for less
than a full loop or for more than a full loop, and may also be at
any desired pitch or at a varying pitch. Four electrodes 36 are
disposed in groove 34 and may be equally circumferentially spaced
about the circumference of the balloon or have another desired
arrangement.
[0050] Of course, variations as discussed above with respect to the
previous figures are applicable to the embodiments of FIGS. 5 and 6
as well.
[0051] FIG. 7A is a schematic view of the distal end region of a
device 12, with the device generally illustrated with a side view
but having the balloon 32 illustrated in a schematic
cross-sectional view. Device 12 is illustrated as being positioned
in situ and extending from the distal end of a guide catheter 14.
Device 12 includes a double-walled balloon 32 and has an inner
balloon wall 56 defining an inner balloon cavity 58, and an outer
balloon wall 60 defining an outer balloon cavity 62. The inner
balloon may be made from a non-compliant or stiffer material. The
inner balloon is preferably sealed (save for the connection to an
inflation lumen) and has no openings to the outer balloon cavity or
to the blood vessel. The inner balloon may have a generally
cylindrical profile. The outer balloon may be made from a
semi-compliant or compliant material and, as discussed below,
preferably includes features such as grooves 34. As can be seen
better with reference to FIG. 7C, which is a cross-sectional view
of the balloon 32 taken at line 7C-7C in FIG. 4A, the outer balloon
has four longitudinally extending grooves 34. The cross-sectional
view of the balloon 32 in FIG. 7A shows the outer balloon wall 60
at the grooves 34 and also the portion of the outer balloon wall
that is visible behind the grooves 34. The balloon 32 may include
other desired features such as a guide wire lumen 40. Electrodes 36
and conductors 38 are generally disposed in the outer balloon
cavity 62 and may be attached to the outer surface of the inner
balloon wall 56 or fixed in another appropriate manner. Micro-pores
to permit seepage of fluid from the outer balloon are disposed
proximate the electrodes 36 and are generally indicated at 64. The
grooves 34 define a gap 42 between the electrodes 36 and the outer
wall when the balloon 32 is inflated.
[0052] FIG. 7B is a cross-sectional view of catheter 30, taken at
line 7B-7B shown in FIG. 7A, illustrating a concentric arrangement
of lumens 40, 72, 74 defined by catheter walls 66, 68, 70, which
lumens are used as a guide wire lumen 40, inner balloon lumen 72
and outer balloon lumen 74. This arrangement is merely an example
arrangement of lumens, and other arrangements are contemplated. For
example, the lumens need not be concentric, or, in some
embodiments, one or more return lumens might be desired. Further,
other conductors 38 might be included for connection with
additional electrodes or sensors.
[0053] This embodiment may used in the procedures and manner
described above, except as noted herein. The nature of the
double-balloon of this embodiment requires the inflation of both
the inner balloon and the outer balloon. The inner balloon may be
inflated to a high pressure, such as 3 atm, and the outer balloon
may be inflated to a much lower pressure to softly and
atraumatically center the distal end region in the blood
vessel.
[0054] It can be appreciated that the variations discussed above,
particularly with respect to the arrangement and number of grooves
and of electrodes are applicable to the embodiment of FIGS. 7A-7C.
For example, there may be more or fewer grooves, the grooves might
extend helically, and/or the electrodes might be staggered
longitudinally. FIG. 8 illustrates a variation of a double-walled
balloon 32 embodiment where a plurality of electrodes 36 are
arranged circumferentially on the outer surface of the inner
balloon wall 56. The outer balloon wall has a circumferential
groove 76 extending around the balloon over the electrodes 36.
Reference numeral 64 indicates that micro-pores are disposed in the
outer balloon wall 60 over the electrodes. FIG. 9 is a detail view
of the circumferential groove of FIG. 8 and shows micro-pores 50
disposed in outer balloon wall 60 over the electrodes 36.
Micro-pores 50 may be disposed elsewhere in the groove 76 proximate
the electrode. For example, the micro-pores may be disposed in the
side walls of the groove.
[0055] FIGS. 10 and 11 illustrate the distal end portion of
double-walled balloon embodiments, where the electrodes 36 are on
the outer surface of the outer balloon wall 60. FIG. 10 depicts an
embodiment where the electrodes are arranged circumferentially
about the balloon and the groove is also circumferential, as in
FIG. 8, and FIG. 11 depicts an embodiment where the electrodes are
arranged in longitudinally extending grooves, as in FIG. 7A. The
outer balloon walls 60 are perforated with micro-pores indicated by
the arrows and at reference numeral 64. It can be appreciated that
the variations and methods of use discussed above are applicable to
these embodiments as well.
[0056] FIG. 12 illustrates the distal end portion of an embodiment
that does not have grooves pre-formed into the balloon wall.
Instead, the compliant outer balloon wall 60 is selectively
restrained as it expands to bulge out around the electrodes 36 and
thereby form grooves 34. Connectors 80 form the electrodes 36 into
a network that restrains the expansion of portions of the balloon.
For example, the circumferentially oriented connectors 80 that
connect the two circumferential bands of electrodes form
circumferential bands that limit the expansion of the balloon in
those areas. The balloon, made from a compliant material, is free
to expand in other locations and so expands around the electrodes
and connectors to form the grooves 34. The outer balloon wall may
preferably include micro-pores in the proximity of the electrodes,
indicated at 64 and by the arrows, to allow fluid seepage from the
outer balloon cavity 62. In some embodiments, the electrodes 36 and
connectors 80 are formed as a single unit that expands when the
balloon is inflated like an expandable stent. Thus, when the
balloon is in the deflated configuration, connectors 80 may form a
zigzag configuration to allow the balloon profile to diminish. In
other embodiments, the connectors 80 may be replaced by
circumferential bands of a non-compliant material of a preset
diameter that are attached to the outer balloon wall 60 under or
over the electrodes 36. The embodiment illustrated is a
double-walled balloon embodiment like that of FIG. 7A, although it
will be appreciated that the unique features of the FIG. 12
embodiment may be readily used with a single-walled balloon
embodiment.
[0057] Balloons used in these embodiments having the preset grooves
may be manufactured by blow molding. In some embodiments, the
grooves are made less compliant, or stiffer, than the other
portions of the balloon. This may be accomplished by making the
wall of the balloon thicker in the areas of the grooves. For
example, the wall thickness of the material of the grooves may be
four times thicker than that of the other portions of the balloons.
This may also be accomplished by adding a layer of higher durometer
material to the groove areas.
[0058] Those skilled in the art will recognize that the present
disclosure may be manifested in a variety of forms other than the
specific embodiments described and contemplated herein.
Accordingly, departure in form a and detail may be made without
departing from the scope and spirit of the present disclosure as
described in the appended claims.
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